The present invention relates to the transport of individual cut sheets of flat flexible media such as paper, vellum, transparencies or the like through a transport path which may have various branches for the delivery of sheets such as printed sheets of media from an input location to a desired location. For the purposes of illustration but not limitation, the invention will be described in the context of a document scanning apparatus having a sheet transport path which extends from a stack of document sheets to be scanned to and through a scanning location to a scanned document location where the scanned sheets are stacked. More particularly, the invention is concerned with the guiding and movement of sheets in a scanning apparatus or printer capable of duplex scanning or printing wherein one side of a media sheet is first scanned or printed and then, if desired, the individual sheets may then be turned over and routed back to the scanning or printing region for scanning or printing the other side of the sheet. The teachings of the invention are applicable generally to any office or business machine in which flexible media sheets must be moved to selected paths.
As used herein, the term "sheet processing apparatus" is therefore intended to broadly include, but not necessarily be limited to, printers, stand alone document copiers, facsimile machines, document scanning machines and combinations of such units.